Add ALTER TABLESPACE ... MOVE command

This adds a 'MOVE' sub-command to ALTER TABLESPACE which allows moving sets of
objects from one tablespace to another.  This can be extremely handy and avoids
a lot of error-prone scripting.  ALTER TABLESPACE ... MOVE will only move
objects the user owns, will notify the user if no objects were found, and can
be used to move ALL objects or specific types of objects (TABLES, INDEXES, or
MATERIALIZED VIEWS).

1 files changed, 171 insertions, 0 deletions

diff --git a/src/backend/commands/tablespace.c b/src/backend/commands/tablespace.c
index 07f5221088f..cb2499af7d2 100644
--- a/src/backend/commands/tablespace.c
+++ b/src/backend/commands/tablespace.c
@@ -59,20 +59,25 @@
 #include "catalog/catalog.h"
 #include "catalog/dependency.h"
 #include "catalog/indexing.h"
+#include "catalog/namespace.h"
 #include "catalog/objectaccess.h"
+#include "catalog/pg_namespace.h"
 #include "catalog/pg_tablespace.h"
 #include "commands/comment.h"
 #include "commands/seclabel.h"
+#include "commands/tablecmds.h"
 #include "commands/tablespace.h"
 #include "common/relpath.h"
 #include "miscadmin.h"
 #include "postmaster/bgwriter.h"
 #include "storage/fd.h"
+#include "storage/lmgr.h"
 #include "storage/standby.h"
 #include "utils/acl.h"
 #include "utils/builtins.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
+#include "utils/lsyscache.h"
 #include "utils/memutils.h"
 #include "utils/rel.h"
 #include "utils/tqual.h"
@@ -956,6 +961,172 @@ AlterTableSpaceOptions(AlterTableSpaceOptionsStmt *stmt)
 }
 
 /*
+ * Alter table space move
+ *
+ * Allows a user to move all of their objects in a given tablespace in the
+ * current database to another tablespace. Only objects which the user is
+ * considered to be an owner of are moved and the user must have CREATE rights
+ * on the new tablespace. These checks should mean that ALTER TABLE will never
+ * fail due to permissions, but note that permissions will also be checked at
+ * that level. Objects can be ALL, TABLES, INDEXES, or MATERIALIZED VIEWS.
+ *
+ * All to-be-moved objects are locked first. If NOWAIT is specified and the
+ * lock can't be acquired then we ereport(ERROR).
+ */
+Oid
+AlterTableSpaceMove(AlterTableSpaceMoveStmt *stmt)
+{
+	List	   *relations = NIL;
+	ListCell   *l;
+	ScanKeyData key[1];
+	Relation	rel;
+	HeapScanDesc scan;
+	HeapTuple	tuple;
+	Oid			orig_tablespaceoid;
+	Oid			new_tablespaceoid;
+
+	/* Ensure we were not asked to move something we can't */
+	if (!stmt->move_all && stmt->objtype != OBJECT_TABLE &&
+		stmt->objtype != OBJECT_INDEX && stmt->objtype != OBJECT_MATVIEW)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("only tables, indexes, and materialized views exist in tablespaces")));
+
+	/* Get the orig and new tablespace OIDs */
+	orig_tablespaceoid = get_tablespace_oid(stmt->orig_tablespacename, false);
+	new_tablespaceoid = get_tablespace_oid(stmt->new_tablespacename, false);
+
+	/* Can't move shared relations in to or out of pg_global */
+	/* This is also checked by ATExecSetTableSpace, but nice to stop earlier */
+	if (orig_tablespaceoid == GLOBALTABLESPACE_OID ||
+		new_tablespaceoid == GLOBALTABLESPACE_OID)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("cannot move relations in to or out of pg_global tablespace")));
+
+	/*
+	 * Must have CREATE rights on the new tablespace, unless it is the
+	 * database default tablespace (which all users implicitly have CREATE
+	 * rights on).
+	 */
+	if (OidIsValid(new_tablespaceoid) && new_tablespaceoid != MyDatabaseTableSpace)
+	{
+		AclResult	aclresult;
+
+		aclresult = pg_tablespace_aclcheck(new_tablespaceoid, GetUserId(),
+										   ACL_CREATE);
+		if (aclresult != ACLCHECK_OK)
+			aclcheck_error(aclresult, ACL_KIND_TABLESPACE,
+						   get_tablespace_name(new_tablespaceoid));
+	}
+
+	/*
+	 * Now that the checks are done, check if we should set either to
+	 * InvalidOid because it is our database's default tablespace.
+	 */
+	if (orig_tablespaceoid == MyDatabaseTableSpace)
+		orig_tablespaceoid = InvalidOid;
+
+	if (new_tablespaceoid == MyDatabaseTableSpace)
+		new_tablespaceoid = InvalidOid;
+
+	/* no-op */
+	if (orig_tablespaceoid == new_tablespaceoid)
+		return new_tablespaceoid;
+
+	/*
+	 * Walk the list of objects in the tablespace and move them. This will
+	 * only find objects in our database, of course.
+	 */
+	ScanKeyInit(&key[0],
+				Anum_pg_class_reltablespace,
+				BTEqualStrategyNumber, F_OIDEQ,
+				ObjectIdGetDatum(orig_tablespaceoid));
+
+	rel = heap_open(RelationRelationId, AccessShareLock);
+	scan = heap_beginscan_catalog(rel, 1, key);
+	while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
+	{
+		Oid			relOid = HeapTupleGetOid(tuple);
+		Form_pg_class relForm;
+
+		relForm = (Form_pg_class) GETSTRUCT(tuple);
+
+		/*
+		 * Do not move objects in pg_catalog as part of this, if an admin
+		 * really wishes to do so, they can issue the individual ALTER
+		 * commands directly.
+		 *
+		 * Also, explicitly avoid any shared tables, temp tables, or TOAST
+		 * (TOAST will be moved with the main table).
+		 */
+		if (IsSystemNamespace(relForm->relnamespace) || relForm->relisshared ||
+			isAnyTempNamespace(relForm->relnamespace) ||
+			relForm->relnamespace == PG_TOAST_NAMESPACE)
+			continue;
+
+		/*
+		 * Only move objects that we are considered an owner of and only
+		 * objects which can actually have a tablespace.
+		 */
+		if (!pg_class_ownercheck(relOid, GetUserId()) ||
+			(relForm->relkind != RELKIND_RELATION &&
+			 relForm->relkind != RELKIND_INDEX &&
+			 relForm->relkind != RELKIND_MATVIEW))
+			continue;
+
+		/* Check if we were asked to only move a certain type of object */
+		if (!stmt->move_all &&
+			((stmt->objtype == OBJECT_TABLE &&
+			  relForm->relkind != RELKIND_RELATION) ||
+			 (stmt->objtype == OBJECT_INDEX &&
+			  relForm->relkind != RELKIND_INDEX) ||
+			 (stmt->objtype == OBJECT_MATVIEW &&
+			  relForm->relkind != RELKIND_MATVIEW)))
+			continue;
+
+		if (stmt->nowait &&
+			!ConditionalLockRelationOid(relOid, AccessExclusiveLock))
+			ereport(ERROR,
+					(errcode(ERRCODE_OBJECT_IN_USE),
+			   errmsg("aborting due to \"%s\".\"%s\" --- lock not available",
+					  get_namespace_name(relForm->relnamespace),
+					  NameStr(relForm->relname))));
+		else
+			LockRelationOid(relOid, AccessExclusiveLock);
+
+		/* Add to our list of objects to move */
+		relations = lappend_oid(relations, relOid);
+	}
+
+	heap_endscan(scan);
+	heap_close(rel, AccessShareLock);
+
+	if (relations == NIL)
+		ereport(NOTICE,
+				(errcode(ERRCODE_NO_DATA_FOUND),
+				 errmsg("no matching relations in tablespace \"%s\" found",
+					orig_tablespaceoid == InvalidOid ? "(database default)" :
+						get_tablespace_name(orig_tablespaceoid))));
+
+	/* Everything is locked, loop through and move all of the relations. */
+	foreach(l, relations)
+	{
+		List	   *cmds = NIL;
+		AlterTableCmd *cmd = makeNode(AlterTableCmd);
+
+		cmd->subtype = AT_SetTableSpace;
+		cmd->name = stmt->new_tablespacename;
+
+		cmds = lappend(cmds, cmd);
+
+		AlterTableInternal(lfirst_oid(l), cmds, false);
+	}
+
+	return new_tablespaceoid;
+}
+
+/*
  * Routines for handling the GUC variable 'default_tablespace'.
  */